Tool holder for flexibly-deformable tool

ABSTRACT

The invention relates to a tool holder ( 1 ) which is intended to receive a flexibly-deformable tool ( 12 ), such as an injection needle or a cutting tool. The operating direction ( 15 ) of the tool is not parallel to the axis ( 14 ) of the tool holder ( 1 ). The inventive tool holder ( 1 ) is characterised in that it ends in a part ( 4 ) of a channel that opens out onto the outside of the body ( 2 ) of the tool holder, comprising a surface having generatrices that are essentially parallel to the axis of the body and enabling the tool ( 12 ) to be introduced by moving same in relation to the axis ( 14 ) of the body of the tool holder. Said tool holder ( 1 ) comprises forms that enable the safe introduction of the needle, simple cleaning, inexpensive manufacture and a quality connection between the needle and the body.

This application is a 371 filing of PCT/IB03/01192 filed Apr. 2, 2003and published Oct. 9, 2003 under publication number WO 03/082387 andclaims priority benefits of French Patent Application No. 02/04093 filedApr. 2, 2002.

FIELD OF THE INVENTION

The present invention concerns a tool holder which is intended toreceive a flexibly deformable tool. It concerns more precisely a toolholder defined according to the preamble of claim 1. The invention alsoconcerns a device comprising such a tool holder and a flexiblydeformable tool.

PRIOR ART

A dental syringe for intraligamentary injection is known from patentapplication FR 2 535 206. This syringe permits injection of productthrough a very fine and flexible needle into the ligaments situatedbetween the jaw bone and the tooth. It is principally composed of anelongate body on which an injection control lever is articulated, acontainer holder housing a container filled with liquid to be injected,and an endpiece comprising the injection needle. In order to resolveproblems of difficult access to the zones where the injections are to begiven, the body of the syringe has an injection head which is at anangle to the axis of the body of the syringe. The removable needle isfitted on the body before performing the injections and is thenwithdrawn afterward. When fitting it in place, the needle is introducedinto the syringe body parallel to the axis of the injection head,undergoing a flexion movement so that its end positions itself parallelto the axis of the container holder. A conical hole serves to guide theneedle during its introduction and provides the stresses necessary forits flexion. The angle between the axis of the injection head and theaxis of the syringe body being considerable, the needle introduced intothe injection head comes into contact with a generatrix of the cone,forming too great an angle with it, and buckles. To overcome thisproblem, a certificate of addition application 2 556 595 to a Frenchpatent provides a channel which opens out at the end of the injectionhead and into the container holder. This channel permits guiding of theneedle from its introduction into the injection head to its emergenceinto the container holder. However, this solution has disadvantages.First, the diameter of the needle and that of the channel beingsubstantially the same, introduction of the needle into the channel isdifficult, or even dangerous. Cases have been reported where the userhas been injured through faulty introduction of the needle. Also, at thearea where the needle is fixed to them, the syringes have zones whichare difficult to clean and disinfect and thus difficult to sterilize.This applies particularly to the curved channel, the perimeter of thecone, and the rear of the injection head. Finally, production of asyringe comprising a curved channel is complicated and, consequently,expensive.

To overcome these problems, FR 2 785 813 discloses an injection syringewhich, at the end of its body, has a channel intended to receive aneedle, and with a conical part whose axis is parallel to the axis ofthe body and which widens toward the outside of the body. The needle isconnected to an internally threaded ring screwed onto a threadedinjection head which forms an angle with the axis of the body. Thissyringe has disadvantages. First, the conical part interferes with thethreaded head so that the thread is nonexistent over a portion of thehead. This detracts from the quality of the connection between the bodyand the needle. Also, when the needle is introduced in a directionparallel to one of the generatrices of the cone, the bevel at the end ofthe needle risks abutting against the opposite generatrix of the cone.This poses risks of injury to the user attempting to position the needlein the channel. Finally, the needle, once it has been curved in itsoperating direction, bears on one of the generatrices of the conicalpart and as a result risks being damaged. The reasons for this is that,in view of the quality of the surface of the conical part, the needledoes not lie on the totality of a generatrix, during its movement offixation to the body, but on several points. In view of the dimensionsof the needle, the pressure exerted by these points on the needle posesa risk of damaging not only its outer part, but also its channel forinjection of product. Such damage necessarily has consequences on theforce that has to be applied to the syringe in order to inject theproduct it contains.

SUMMARY OF THE INVENTION

The object of the invention is to make available a tool holder and adevice comprising a tool holder and a flexibly deformable toolovercoming these disadvantages and improving the known devices of theprior art. In particular, the invention proposes a reliable device whichcan be cleaned and disinfected easily, has a simple geometry making itpossible to minimize the production costs, and permitting a qualityconnection between the needle and the body of the tool holder, goodguidance of the needle during its introduction into the body, andminimizing the risks of damage to the needle during its connection tothe body.

The tool holder according to the invention is characterized by thecharacterizing part of claim 1.

Claims 2 through 7 define variants of the tool holder.

The device comprising such a tool holder and a flexibly deformable toolis defined by independent claim 8.

Claims 9 through 11 define variants of the device.

BRIEF DESCRIPTION OF THE DRAWINGS

Two embodiments of the invention, given as examples, are shown in theattached drawing.

FIG. 1 shows an overall view of a device according to the invention,comprising a tool holder and a flexibly deformable tool.

FIG. 2 shows a diagrammatic cross section of a tool holder according tothe invention, receiving a cutting tool which is flexibly deformableelastically.

FIG. 3 is a cross section of the device according to the invention, theflexibly deformable tool being shown in two positions corresponding totwo stages in the method of joining it to the tool holder.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The device 10 shown in FIG. 1 is a syringe for injecting liquids orpastes. It comprises a tool holder 1 and a lever 11 acting on amechanism (not shown) for controlling the displacement of a thrustcylinder which causes ejection of the liquid or paste through a needle12. It should be noted that the needle 12 can either be flexiblydeformable elastically or can be flexibly deformable beyond the elasticrange of the material from which it is made. The tool holder 1 comprisesa body 2 in which a reservoir 6 is formed which can directly receive theliquid or paste to be injected or a container filled with liquid orpaste to be injected. At the bottom of the reservoir 6 a channel isformed which comprises a cylindrical part 3 parallel to the axis of thebody 2. This channel 3 ends in a part 4 which is in the form of adivergent cone opening to the outside of the body 2 in the area of thesupport 5 of the injection needle 12. The support 5 is threaded, forexample, and permits connection of the needle 12 to the body 2. Theconical part 4 has the shape of a cone of revolution, of which one ofthe generatrices is substantially parallel to the axis of thecylindrical part 3 of the channel.

The needle 12 is connected to a ring 13 which, for example, has aninternal thread allowing it to be joined to the support 5 of the body 2.

To assemble the needle 12 and the body 2, the needle 12 is introducedinto the conical part 4. In order to ensure good penetration of theneedle into the cylindrical part of the channel, the needle can inparticular be pressed against the cone in the area of the generatrixparallel to the axis of the body. The needle is thus substantiallyparallel to the cylindrical part of the channel. The needle is thenintroduced into the cylindrical part 3 by means of a translationalmovement thereof in the axis 14 of the body 2. The needle 12 is thensituated in the position shown by dotted lines in FIG. 3. This method ofintroducing the needle makes it possible to preserve its end penetratinginto the body. Flexion of the needle 12 is then effected so as to bringits free end into the direction determined by the axis 15 of the support5. The needle 12 is then situated in the position shown by solid linesin FIG. 3. The internally threaded ring 13 integral with the needle 12is then screwed onto the support 5. During this action, the needle 12penetrates a little farther into the channel 3. Thus, the needle isjoined to the body in three stages:

-   -   a stage in which the needle is introduced into the channel,    -   a stage involving flexion of the needle,    -   a stage in which the needle is fixed to the body.

To remove the needle 12 from the body 2, the internally threaded ring 13connected to the needle 12 is unscrewed from the support 5. As theneedle 12 is no longer held in position on the support 5, it can bewithdrawn from the channel by means of a translational movement thereofin the axis 14 of the body 2.

By virtue of this method of assembly, the actions comprisingintroduction of the needle 12 into the body 2 and flexion of the needle12 take place one after the other. They are independent and,consequently, are easier to perform.

It should be noted that the cone 4 can be replaced by any configurationensuring that the needle can be guided toward the cylindrical part 3 ofthe channel by virtue of a surface whose generatrices are substantiallyparallel to the axis of this cylindrical part, and ensuring that theneedle does not come into contact against this configuration during itsstages of flexion and of fixing and when it is in its operatingposition.

In a second embodiment, the body 22 of the tool holder 21 is applied toa drilling, milling, hammering or vibrating device intended, forexample, for the field of dental surgery. The body 22 of the tool holder21 comprises a pneumatic motor 23 or an electric motor driving aspeed-reducing gear 24 or speed-increasing gear. It can also compriseany type of transducer with which it is possible to set in motion,either directly or indirectly, the tool or the assembly consisting ofthe body and of the tool. The speed-reducing gear 24 or speed-increasinggear drives a spindle 25 which has an axis parallel to the body 22. Thespindle 25 has a channel 32 passing through it and receiving a tool 26which is flexibly deformable elastically, for example a drill bit or ahollow or solid milling cutter. The spindle 25 is in a pivot connectionin the body 22. The tool 26 and the spindle 25 between them having atight fit, the tool 26 is driven in rotation by friction.

The spindle ends in a divergent cone 27 opening out from the body 22 inthe area of the support 28 of the tool 26. This support 28 is threadedand allows the tool 26 to be connected to the body 22. The cone 27 is acone of revolution, of which one of the generatrices is substantiallyparallel to the axis of the spindle 25.

The tool 26 is connected by a pivot connection to a ring 29 for guidingit. This ring has an internal thread allowing it to be joined to thesupport 28 of the body 22.

To assemble the tool 26 and the body 22, the tool 26 is introduced intothe cone 27, then into the spindle 25 by means of a translationalmovement thereof along the axis 31 of the body 22. Flexion of the tool26 is then effected in such a way as to bring its free end into theoperating direction of the tool as determined by the axis 30 of thesupport. Finally, the internally threaded ring 29 connected to the tool26 is screwed onto the support 28. During this action, the tool 26penetrates a little farther into the channel 32 of the spindle 25.

To remove the tool 26 from the body, the internally threaded ring 29 isunscrewed from the support 28. As the tool 26 is no longer held inposition on the support, it returns to its initial rectilinear positionby virtue of its elastic characteristics. Finally, the tool 26 iswithdrawn from the spindle 25 by means of a translational movementthereof along the axis 31 of the body 22.

A variant of this second embodiment differs from said second embodimentin that the device comprises an injection needle instead of the cuttingtool and in that it comprises, in place of the motor 23 and thespeed-reducing gear 24, a device permitting orientation of the needle inrotation about its axis, for example alternately, thus making itpossible to position the bevel of the needle with respect to the surfaceto be penetrated in order to perform the injection. Such a device fororientation of a needle is described for example in patent applicationFR 2 473 318.

In the two embodiments described above, the tool is fitted in the bodyof the tool holder by screwing. However, this can be done by any otherknown means, for example a bayonet-type connection or shape-fitconnection. Depending on the means of fixing used, the movement of theneedle with respect to the body is different during the stage in whichit is fixed to the body.

1. A tool holder (1; 21) intended to receive a flexibly deformable tool(12; 26), comprising an elongate body (2; 22) with a channel intended toreceive the end of the tool (12; 26), the channel having a cylindricalpart (3; 32) parallel to the body (2; 22) and a part (4; 27) opening tothe outside of the body (2; 22), widening toward the outside of the body(2; 22) and guiding the tool (12; 26) toward the cylindrical part (3;32) when it is being fitted in the tool holder (1; 21), and means (5,13; 28, 29) which keep the tool (12; 26) in position and are arranged insuch a way that the axis of the tool (12; 26) in the operating phase isnot parallel to the axis of the body (2; 22), the part (4; 27) whichopens to the outside of the body (2; 22) permitting introduction of thetool (12; 26) into the body (2; 22) by a displacement of the tool (12;26) along the axis of the cylindrical part (3; 32) of the channel,wherein the part (4; 27) opening to the outside of the body comprises asurface whose generatices are substantially parallel to the axis of thecylindrical part of the channel and which extends from the cylindricalpart (3; 32) to outside of the body.
 2. The tool holder as claimed inclaim 1, wherein the part (4; 27) opening to the outside of the body hasconfigurations allowing it to avoid contact with the tool during itsstages of flexion and fixation and when said tool is in the operatingposition.
 3. The tool holder as claimed in claim 1, wherein the means(5, 13; 28, 29) for holding the tool (12; 26) in position comprise, onthe body (2; 22), a threaded end (5; 28) onto which an internallythreaded ring (13; 29) connected to the tool (12; 26) is screwed.
 4. Thetool holder as claimed in claim 1, wherein the means for holding thetool (12; 26) in position comprise, on the body, an end which cooperateswith a ring connected to the tool (12; 26) in order to form abayonet-type connection system.
 5. The tool holder as claimed in claim1, wherein the means for holding the tool (12; 26) in position comprise,on the body, clip means which cooperate with complementary clip means ona ring connected to the tool (12; 26).
 6. The tool holder as claimed inclaim 1, wherein the means for holding the tool (12; 26) in positioncomprise, on the body, shape-fit means which cooperate withcomplementary shape-fit means on a ring connected to the tool (12; 26).7. The tool holder as claimed in claim 1, wherein, in the area of thecylindrical part of the channel (3; 32), it has means (25) for guidingthe tool (26) in rotation.
 8. A device comprising the tool holder (1;21) as claimed in claim 1 and a flexibly deformable tool (12; 26)connected to a ring (13; 29).
 9. The device as claimed in claim 8,wherein the tool (12; 26) is connected to the ring (29) by a pivotconnection.
 10. The device as claimed in claim 8, wherein the tool (12)is an injection needle.
 11. The device as claimed in claim 9, whereinthe tool holder (21) has means (23, 24, 25) for driving the tool (26) inrotation.